The quantitation of gold-labelled macromolecules on cell surfaces by X-ray microanalysis

1992 ◽  
Vol 23 (3) ◽  
pp. 391-392
Author(s):  
Non Thomas ◽  
Iolo ap Gwynn
Keyword(s):  
Cell Surfaces ◽  
X Ray

The Use of X-Ray Photoelectron Spectroscopy for the Study of Oral Streptococcal Cell Surfaces

1997 ◽  
Vol 11 (4) ◽  
pp. 388-394 ◽  
Author(s):  
H.C. Van Der Mei ◽  
H.J. Busscher
Keyword(s):  
Cell Surface ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Cell Surface Hydrophobicity ◽  
Surface Hydrophobicity ◽  
Contact Angles ◽  
Microbial Cell ◽  
Cell Surfaces ◽  
Water Contact ◽  
X Ray

Physicochemical and structural properties of microbial cell surfaces play an important role in their adhesion to surfaces and are determined by the chemical composition of the outermost cell surface. Many traditional methods used to determine microbial cell wall composition require fractionation of the organisms and consequently do not yield information about the composition of the outermost cell surface. X-ray photoelectron spectroscopy (XPS) measures the elemental composition of the outermost cell surfaces of micro-organisms. The technique requires freeze-drying of the organisms, but, nevertheless, elemental surface concentration ratios of oral streptococcal cell surfaces with peritrichously arranged surface structures showed good relationships with physicochemical properties measured under physiological conditions, such as zeta potentials. Isoelectric points ap-peared to be governed by the relative abundance of oxygen- and nitrogen-containing groups on the cell surfaces. Also, the intrinsic microbial cell-surface hydrophobicity by water contact angles related to the cell-surface composition as by XPS and was highest for strains with an elevated isoelectric point. Inclusion of elemental surface compositions for tufted streptococcal strains caused deterioration of the relationships found. Interestingly, hierarchical cluster analysis on the basis of the elemental surface compositions revealed that, of 36 different streptococcal strains, only four S. rattus as well as nine S. mitis strains were located in distinct groups, well separated from the other streptococcal strains, which were all more or less mixed in one group.

scholarly journals Neural Stem Cell Spreading on Lipid Based Artificial Cell Surfaces, Characterized by Combined X-ray and Neutron Reflectometry

Materials ◽  
2010 ◽  
Vol 3 (11) ◽  
pp. 4994-5006 ◽  
Author(s):  
Martin Huth ◽  
Samira Hertrich ◽  
Gabor Mezo ◽  
Emilia Madarasz ◽  
Bert Nickel
Keyword(s):  
Stem Cell ◽  
Neural Stem Cell ◽  
Cell Spreading ◽  
Neutron Reflectometry ◽  
Cell Surfaces ◽  
X Ray ◽  
Artificial Cell

scholarly journals The S-Layer Glycome—Adding to the Sugar Coat of Bacteria

2011 ◽  
Vol 2011 ◽  
pp. 1-16 ◽  
Author(s):  
Robin Ristl ◽  
Kerstin Steiner ◽  
Kristof Zarschler ◽  
Sonja Zayni ◽  
Paul Messner ◽  
...  
Keyword(s):  
Unique Feature ◽  
Nanometer Scale ◽  
Capsular Polysaccharides ◽  
Glycosidic Linkage ◽  
Cell Surfaces ◽  
X Ray ◽  
Tyrosine Residues ◽  
X Ray Crystallography ◽  
Gram Positive Bacteria ◽  
Self Assembling

The amazing repertoire of glycoconjugates present on bacterial cell surfaces includes lipopolysaccharides, capsular polysaccharides, lipooligosaccharides, exopolysaccharides, and glycoproteins. While the former are constituents of Gram-negative cells, we review here the cell surface S-layer glycoproteins of Gram-positive bacteria. S-layer glycoproteins have the unique feature of self-assembling into 2D lattices providing a display matrix for glycans with periodicity at the nanometer scale. Typically, bacterial S-layer glycans are O-glycosidically linked to serine, threonine, or tyrosine residues, and they rely on a much wider variety of constituents, glycosidic linkage types, and structures than their eukaryotic counterparts. As the S-layer glycome of several bacteria is unravelling, a picture of how S-layer glycoproteins are biosynthesized is evolving. X-ray crystallography experiments allowed first insights into the catalysis mechanism of selected enzymes. In the future, it will be exciting to fully exploit the S-layer glycome for glycoengineering purposes and to link it to the bacterial interactome.

scholarly journals En route to photoaffinity labeling of the bacterial lectin FimH

2010 ◽  
Vol 6 ◽  
pp. 810-822 ◽  
Author(s):  
Thisbe K Lindhorst ◽  
Michaela Märten ◽  
Andreas Fuchs ◽  
Stefan D Knight
Keyword(s):  
Escherichia Coli ◽  
Photoaffinity Labeling ◽  
Carbohydrate Recognition Domain ◽  
Cell Surfaces ◽  
Carbohydrate Recognition ◽  
Dot Blot ◽  
X Ray ◽  
Receptor Interactions ◽  
Carbohydrate Recognition Domains ◽  
Dot Blot Analysis

Mannose-specific adhesion ofEscherichia colibacteria to cell surfaces, the cause of various infections, is mediated by a fimbrial lectin, called FimH. X-ray studies have revealed a carbohydrate recognition domain (CRD) on FimH that can complex α-D-mannosides. However, as the precise nature of the ligand–receptor interactions in mannose-specific adhesion is not yet fully understood, it is of interest to identify carbohydrate recognition domains on the fimbrial lectin also in solution. Photoaffinity labeling serves as an appropriate methodology in this endeavour and hence biotin-labeled photoactive mannosides were designed and synthesized for photoaffinity labeling of FimH. So far, the photo-crosslinking properties of the new photoactive mannosides could be detailed with the peptide angiotensin II and labeling of FimH was shown both by MS/MS studies and by affino dot–blot analysis.

X-ray photoelectron spectroscopy for the study of microbial cell surfaces

2000 ◽  
Vol 39 (1) ◽  
pp. 1-24 ◽  
Author(s):  
H.C. van der Mei ◽  
J. de Vries ◽  
H.J. Busscher
Keyword(s):  
Photoelectron Spectroscopy ◽  
Microbial Cell ◽  
Cell Surfaces ◽  
X Ray

scholarly journals X-Ray Photoelectron Spectroscopy on Microbial Cell Surfaces: A Forgotten Method for the Characterization of Microorganisms Encapsulated With Surface-Engineered Shells

2021 ◽  
Vol 9 ◽  
Author(s):  
Hao Wei ◽  
Xiao-Yu Yang ◽  
Henny C. van der Mei ◽  
Henk J. Busscher
Keyword(s):  
Cell Surface ◽  
Photoelectron Spectroscopy ◽  
Surface Characterization ◽  
Elevated Temperatures ◽  
High Vacuum ◽  
Microbial Cell ◽  
Cell Surfaces ◽  
Microbial Cells ◽  
X Ray ◽  
Freeze Dried

Encapsulation of single microbial cells by surface-engineered shells has great potential for the protection of yeasts and bacteria against harsh environmental conditions, such as elevated temperatures, UV light, extreme pH values, and antimicrobials. Encapsulation with functionalized shells can also alter the surface characteristics of cells in a way that can make them more suitable to perform their function in complex environments, including bio-reactors, bio-fuel production, biosensors, and the human body. Surface-engineered shells bear as an advantage above genetically-engineered microorganisms that the protection and functionalization added are temporary and disappear upon microbial growth, ultimately breaking a shell. Therewith, the danger of creating a “super-bug,” resistant to all known antimicrobial measures does not exist for surface-engineered shells. Encapsulating shells around single microorganisms are predominantly characterized by electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, particulate micro-electrophoresis, nitrogen adsorption-desorption isotherms, and X-ray diffraction. It is amazing that X-ray Photoelectron Spectroscopy (XPS) is forgotten as a method to characterize encapsulated yeasts and bacteria. XPS was introduced several decades ago to characterize the elemental composition of microbial cell surfaces. Microbial sample preparation requires freeze-drying which leaves microorganisms intact. Freeze-dried microorganisms form a powder that can be easily pressed in small cups, suitable for insertion in the high vacuum of an XPS machine and obtaining high resolution spectra. Typically, XPS measures carbon, nitrogen, oxygen and phosphorus as the most common elements in microbial cell surfaces. Models exist to transform these compositions into well-known, biochemical cell surface components, including proteins, polysaccharides, chitin, glucan, teichoic acid, peptidoglycan, and hydrocarbon like components. Moreover, elemental surface compositions of many different microbial strains and species in freeze-dried conditions, related with zeta potentials of microbial cells, measured in a hydrated state. Relationships between elemental surface compositions measured using XPS in vacuum with characteristics measured in a hydrated state have been taken as a validation of microbial cell surface XPS. Despite the merits of microbial cell surface XPS, XPS has seldom been applied to characterize the many different types of surface-engineered shells around yeasts and bacteria currently described in the literature. In this review, we aim to advocate the use of XPS as a forgotten method for microbial cell surface characterization, for use on surface-engineered shells encapsulating microorganisms.

scholarly journals THE ELECTRON MICROSCOPY OF THE HUMAN HAIR FOLLICLE

1957 ◽  
Vol 3 (2) ◽  
pp. 203-214 ◽  
Author(s):  
M. S. C. Birbeck ◽  
E. H. Mercer
Keyword(s):  
Wide Angle ◽  
Essential Factor ◽  
Cell Surfaces ◽  
Human Hair Follicle ◽  
Cortical Cells ◽  
Amorphous Substance ◽  
X Ray ◽  
Cystine Content ◽  
Adhesive Cement ◽  
Intercellular Gaps

1. The presumptive cortical cells of hair in the undifferentiated matrix of the bulb contain mitochondria, agranular vesicles, and many small dense R.N.P. particles, but no keratin, pigment granules, or endoplasmic reticulum. 2. In the mid-bulb region intercellular adhesion is limited to small localised areas. Intercellular gaps are common and the cell surfaces are irregularly convoluted. The melanocyte processes penetrate the cell gaps. The relation between their pigment-bearing tips and the involutions of the cell membranes suggests an active phagocytosis of the tips. 3. Fibrous keratin first appears in loose parallel strands of fine filaments (ca. 60 A diameter) in the mid-bulb. The filaments, the long mitochondria, and elongated nucleus are all parallel to the long axis of the cell and the axis of the follicle. 4. At the level of the constriction of the bulb and above, a dense amorphous substance appears between the fine filaments and apparently acts as adhesive cement. The bundles of filaments now form well defined fibrils. The packing of the filaments within the fibrils is in places hexagonal and elsewhere in the form of "whorls." 5. At higher levels further filaments and interfilamentous cement are added together and the whole cytoplasmic space becomes packed with fibrils which finally condense to massive blocks of keratin. The residual cellular material occupies the interstices. 6. The addition of the interfilamentous substance is regarded as an essential factor in keratinisation. Keratin is considered to be a complex made of fine filaments (α-filaments) embedded in an amorphous substance (γ-keratin) which has the higher cystine content. 7. The wide-angle fibre-type x-ray pattern is thought to be due to scattering by the fine α-filaments and some low angle lateral spacings to the filament-plus-cement structure.

Energy Dispersive X-Ray Examination of Cell Surface Antigen Sites

1976 ◽  
Vol 34 ◽  
pp. 36-37
Author(s):  
T. A. Barber
Keyword(s):  
Electron Microscopy ◽  
Cell Surface ◽  
Surface Antigen ◽  
Energy Dispersive ◽  
Cell Surface Antigen ◽  
Cell Surfaces ◽  
X Ray ◽  
Recent Developments ◽  
Immunologic Marker ◽  
Scanning Electron

Immunolabeling for transmission and scanning electron microscopy allows examination at high resolution of cell surface antioen sites. In procedures used with the scanning electron microscope significant problems are associated with non-specific labeling, aggregation of labeled particles, the attachment of label particles to cell surfaces by comparatively weak antigenantibody bonds, and quantitation of amounts of immunologic marker at a cell's surface. In the light of recent developments in elemental analysis of biological materials through the use of x-ray snectra (1), it seems desirable to explore the use of energy dispersive x-ray analysis (EDXA) in the examination of cell surface antigen sites.

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